ACT001 inhibits pituitary tumor growth by inducing autophagic cell death via MEK4/MAPK pathway.

ACT001, derived from traditional herbal medicine, is a novel compound with effective anticancer activity in clinical trials. However, little is known regarding its role in pituitary adenomas. Here, we demonstrated that ACT001 suppressed cell proliferation and induced cell death of pituitary tumor cells in vitro and in vivo. ACT001 was also effective in suppressing the growth of different subtypes of human pituitary adenomas. The cytotoxic mechanism ACT001 employed was mainly related to autophagic cell death (ACD), indicated by autophagosome formation and LC3-II accumulation. In addition, ACT001-mediated inhibitory effect decreased when either ATG7 was downregulated or cells were cotreated with autophagy inhibitor 3-methyladenine (3-MA). RNA-seq analysis showed that mitogen-activated protein kinase (MAPK) pathway was a putative target of ACT001. Specifically, ACT001 treatment promoted the phosphorylation of JNK and P38 by binding to mitogen-activated protein kinase kinase 4 (MEK4). Our study indicated that ACT001-induced ACD of pituitary tumor cells via activating JNK and P38 phosphorylation by binding with MEK4, and it might be a novel and effective anticancer drug for pituitary adenomas.

Antiproliferative and apoptosis-inducing activity of schisandrin B against human glioma cells.

BACKGROUND: Malignant glioma is the most devastating and aggressive tumour in the brain and is characterised by high morbidity, high mortality and extremely poor prognosis. The main purpose of the present study was to investigate the effects of schisandrin B (Sch B) on glioma cells both in vitro and in vivo and to explore the possible anticancer mechanism underlying Sch B-induced apoptosis and cell cycle arrest. METHODS: The anti-proliferative ability of Sch B on glioma cells were assessed by MTT and clony formation assays. Flow cytometric analysis was used to detect cell cycle changes. Apoptosis was determined by Hoechst 33342 staining and annexin V/PI double-staining assays. The mitochondrial membrane potential was detected by Rhodamine 123 staining. The in vivo efficacy of Sch B was measured using a U87 xenograft model in nude mice. The expressions of the apoptosis-related and cell cycle-related proteins were analysed by western blot. Student's t-test was used to compare differences between treated groups and their controls. RESULTS: We found that Sch B inhibited growth in a dose- and time-dependent manner as assessed by MTT assay. In U87 and U251 cells, the number of clones was strongly suppressed by Sch B. Flow cytometric analysis revealed that Sch B induced cell cycle arrest in glioma cells at the G0/G1 phase. In addition, Sch B induced glioma cell apoptosis and reduced mitochondrial membrane potential (ΔΨm) in a dose-dependent manner. Mechanically, western blot analysis indicated that Sch B induced apoptosis by caspase-3, caspase-9, PARP, and Bcl-2 activation. Moreover, Sch B significantly inhibited tumour growth in vivo following the subcutaneous inoculation of U87 cells in athymic nude mice. COCLUSIONS: In summary, Sch B can reduce cell proliferation and induce apoptosis in glioma cells and has potential as a novel anti-tumour therapy to treat gliomas.

Necroptosis signaling and mitochondrial dysfunction cross-talking facilitate cell death mediated by chelerythrine in glioma.

Glioma is the most common primary malignant brain tumor with poor survival and limited therapeutic options. Chelerythrine (CHE), a natural benzophenanthridine alkaloid, has been reported to exhibit the anti-tumor effects in a variety of cancer cells. However, the molecular target and the signaling process of CHE in glioma remain elusive. Here we investigated the underlying mechanisms of CHE in glioma cell lines and glioma xenograft mice model. Our results found that CHE-induced cell death is associated with RIP1/RIP3-dependent necroptosis rather than apoptotic cell death in glioma cells at the early time. Mechanism investigation revealed the cross-talking between necroptosis and mitochondria dysfunction that CHE triggered generation of mitochondrial ROS, mitochondrial depolarization, reduction of ATP level and mitochondrial fragmentation, which was the important trigger for RIP1-dependent necroptosis activation. Meanwhile, PINK1 and parkin-dependent mitophagy promoted clearance of impaired mitochondria in CHE-incubated glioma cells, and inhibition of mitophagy with CQ selectively enhanced CHE-induced necroptosis. Furthermore, early cytosolic calcium from the influx of extracellular Ca2+ induced by CHE acted as important "priming signals" for impairment of mitochondrial dysfunction and necroptosis. Suppression of mitochondrial ROS contributed to interrupting positive feedback between mitochondrial damage and RIPK1/RIPK3 necrosome. Lastly, subcutaneous tumor growth in U87 xenograft was suppressed by CHE without significant body weight loss and multi-organ toxicities. In summary, the present study helped to elucidate necroptosis was induced by CHE via mtROS-mediated formation of the RIP1-RIP3-Drp1 complex that promoted Drp1 mitochondrial translocation to enhance necroptosis. Our findings indicated that CHE could potentially be further developed as a novel therapeutic strategy for treatment of glioma.

[Rapid Detection of Trace Enrofloxacin and Ciprofloxacin in Drinking Water by SERS].

In recent years, the abuse of antibiotics has led to the spread and diffusion of antibiotic resistance genes in the environment, which poses a potential threat to the ecosystem and human health. In particular, the related reports of antibiotic contamination in drinking water have aroused great social concerns. Therefore, realizing the rapid detection of trace antibiotics in emergency events has become a research hotspot. Here, in combination with magnetic solid phase extraction (MSPE), we established a rapid detection strategy for ng·L-1 level quinolones in drinking water using surface-enhanced Raman spectroscopy (SERS). With the help of the high enrichment capacity provided by the high adsorption capacity of the magnetic graphene oxide composite nanomaterial (Fe3O4@SiO2-GO), the spiked detection of 1.0 ng·L-1 enrofloxacin (ENR) and 5.0 ng·L-1 ciprofloxacin (CIP) in drinking water was successfully achieved, with recoveries ranging from 77.5% to 91.5%, which met the current requirements of drinking water testing. For environmental water samples such as lake water, the selectivity of extraction materials needs to be further improved due to the strong interference of the complex organic matrix.

Rapid qualitative and quantitative analysis of trace aconitum phytotoxin by SERS.

The dual functions of phytotoxin, such as aconitine, with biological activity and toxicity ignited the related food poisoning intentionally or accidentally from time to time. The fast and accurate qualitative analysis is a prerequisite for tracking the source of poisoning and taking correct treatments. Taking the single molecule level sensitivity and molecular fingerprinting of Surface-enhanced Raman spectroscopy (SERS), we developed a highly sensitive and accurate strategy for the trace detection of three structurally similar aconitines (ATs) (aconitine, mesaconitine and hypoaconitine) by employing the 100 nm Ag NPs colloid as the SERS substrate. It was figured out that the lowest detectable concentration is in the level of 5.0 µg/L for these three ATs with the linear range of 5.0-100.0 µg/L. The qualitative and quantitative analysis of trace ATs spiked in various food samples was realized in 3 mins, which demonstrated the SERS based strategy is very promising towards the fast and on-site detection of ATs in the field of food safety or criminal identification.

Dopamine agonist resistance-related endocan promotes angiogenesis and cells viability of prolactinomas.

Dopamine agonists (DAs) are the first-line treatment of prolactinomas. They function through the dopamine 2 receptor (D2R) in the tumor cells. Endocan, also called endothelial cell-specific molecule-1 (ESM1), has been described as a marker of neoangiogenesis. However, whether ESM1 promotes the resistance of prolactinomas to DA therapy is largely unknown. In our study, 25 patients with prolactinomas were divided into resistant- and sensitive- groups according to the clinical response to bromocriptine. We found that ESM1-microvessel density of resistant prolactinomas was significantly higher than that of sensitive prolactinomas (47.9 ± 11.6, n = 8, vs 13.1 ± 2.8, n = 17, p = 0.0006), indicating that ESM1 was a DA resistance-related gene. Immunostaining showed that ESM1 was expressed in tumor vessels and sporadic tumor cells, and ESM1 was overlapped with the Smooth Muscle Actin (SMA) and von Willebrand Factor (VWF) in the tumor vessels. Silencing of ESM1 markedly suppressed the viability of GH3 and MMQ cells in vitro, and furthermore, significantly increased the sensitivity of GH3 and MMQ cells to DA treatment. Additionally, silencing of ESM1 down-regulated the angiogenesis-associated genes, such as VEGFR2, FGF2, CD34, CD31, VWF, and EGFR. Knockdown of ESM1 decreased endothelial tube formation of HUVECs, and significantly increased the sensitivity of HUVECs to Avastin treatment. Therefore, we first demonstrate that DA resistance-related ESM1 promotes the angiogenesis and tumor cells growth of prolactinomas, suggesting that ESM1 may be a novel therapeutic target for prolactinomas.

MicroRNA expression profile of bromocriptine-resistant prolactinomas.

MicroRNAs (miRNA) have been implicated in the resistance of tumors to chemotherapy. However, little is known about miRNA expression in bromocriptine-resistant prolactinomas. In this study, 23 prolactinoma samples were classified as bromocriptine-sensitive or -resistant according to the clinical definition of bromocriptine resistance, and their miRNA expression profiles were determined using Solexa sequencing. We found 41 miRNAs that were differentially expressed between the two groups, and 12 of these were validated by stem-loop qRT-PCR. Hsa-mir-93, hsa-mir-17, hsa-mir-22*, hsa-mir-126*, hsa-mir-142-3p, hsa-mir-144*, hsa-mir-486-5p, hsa-mir-451, and hsa-mir-92a were up-regulated and hsa-mir-30a, hsa-mir-382, and hsa-mir-136 were down-regulated in bromocriptine-resistant prolactinomas in comparison with bromocriptine-sensitive prolactinomas. Furthermore, silencing of mir-93 significantly increased the sensitivity of MMQ cells to dopamine agonist treatment. Mir-93 directly affected p21 expression in MMQ cells by targeting the 3'-UTR. Our study is the first to identify a miRNA expression profile associated with bromocriptine-resistant prolactinoma.

High-mobility group box 2 is associated with prognosis of glioblastoma by promoting cell viability, invasion, and chemotherapeutic resistance.

BACKGROUND: The expression profile of high-mobility group box 2 (HMGB2) in patients with glioblastoma multiforme (GBM) and its clinical signature with underlying mechanisms were not fully explored. METHODS: HMGB2 protein levels were measured in 51 GBM patients by immunohistochemical studies. To clarify the precise role of HMGB2 on cell invasion and viability of 3 GBM cell lines, we did in vitro and in vivo analyses with lentivirus vectors and small interfering RNA. Transwell invasion assays and wound-healing assays were used to analyze the invasion of GBM cells. Expression of p53 and matrix metalloproteinase 2/tissue inhibitors of metalloproteinase 2 (MMP2/TIMP2) protein was analyzed by Western blot. RESULTS: HMGB2 protein expression was significantly higher in GBM than in controlled brain tissues (P < .0001). HMGB2 overexpression was significantly correlated with shorter overall survival time, which was the only independent prognostic factor for overall survival in a multivariate analysis (P = .017). HMGB2 knockdown by small interfering RNA decreased cell viability and invasion in vitro and significantly decreased tumor volume in vivo, which might be involved in the change of p53 expression and the balance of MMP2/TIMP2. Moreover, silencing of HMGB2 could significantly increase the sensitivity of GBM cells to temozolomide chemotherapy. CONCLUSIONS: Our present data suggest that HMGB2 expression is a significant prognostic factor and might play an important role in cell invasion and temozolomide-induced chemotherapeutic sensitivity of GBM. This study highlights the importance of HMGB2 as a novel prognostic marker and an attractive therapeutic target of GBM.

The miR-92b functions as a potential oncogene by targeting on Smad3 in glioblastomas.

MicroRNAs(miR) play an important role in cell growth, differentiation, proliferation and apoptosis, which can function either as oncogenes or as tumor suppressors in their effect on tumor growth. Smad3 is often underexpressed in very diverse types of malignant tumors and has an important tumor suppressive function; however, the underlying mechanism in solid cancer including glioblastomas(GBM) is not fully explored. The aim of this study is to explore the role of miR-92b in regulation of smad3 in GBM. In our study, we found that miR-92b expression was significantly increased in GBM tissues compared with normal brain tissues by Q-RT-PCR and in situ hybridization (P<0.01). However, expression of smad3 in GBM samples was significantly reduced compared with normal brain tissues by western blot and immunohistochemistry (P<0.05). Using 3'UTR luciferase reporter gene assay, we found that miR-92b directly affected smad3 expression in GBM cells by targeting the 3'-untranslated region. Silencing of miR-92b was able to significantly inhibit the viability of GBM cells in three GBM cell lines through up-regulating the TGF-beta/smad3/p21 signaling pathway in vitro. Furthermore, the tumor growth and the weight of U87 cells in the miR-92b inhibitor group were significantly inhibited when compared with that of the control group in vivo. Our data demonstrated that miR-92b may be considered as a tumor oncogene to promote GBM cell proliferation, and thus may serve as a potentially useful target for development of miRNA-based therapies in the future.